The most powerful ingredient in fueling strong stamina and energy in kendo is deep breathing and control of breathing. Practice deep breathing by quickly inhaling and slowly exhaling through your partially open mouth, extending your abdomen to draw in as much oxygen as possible. Practice breathing carefully and quietly, in kendo we must never show our opponent when we are taking in a breath or exhaling. When completing an attack do not exhale completely but have enough oxygen to attack again, inhale quickly and quietly using your abdomen. The goal is to keep as much oxygen in your lungs as possible to extend the times in which you need to inhale. Once you become aware of your breathing and practice deep breathing your stamina and energy will improve.